CRISTINA, J.; IWANIEC, T.; V. KOVALEV, L.; ONNINEN, J. The Hopf-Laplace equation: harmonicity and regularity. ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE, [S. l.], v. 13, n. 4, p. 1145-1187, 2014. DOI: 10.2422/2036-2145.201203_006. Disponível em: https://journals.sns.it/index.php/annaliscienze/article/view/367. Acesso em: 21 mar. 2025.